Fixing cementitious objects, e.g. fiber cement objects, such as fiber cement sheets, e.g. EQUITONE [Tectiva]® façade plates to a supporting structure, such as a metal or wooden frame, is known. Typically these façade plates are mounted and fixed to wooden frames by means of screw fixing. For metal frame support structures, screwing or riveting is used.
A difficulty is to have the cementitious objects, e.g. fiber cement objects, typically sheets, fixed to the support, while still allowing minor displacements of the fiber cement objects in at least 2, and sometimes 3 directions. Displacements in the two planar directions and perpendicular to the sheet surface are always to be foreseen. The displacements in planar direction of such sheets, in particular for fiber cement sheets, may be caused by hydric movement (expansion and shrinkage due to water absorption and desorption) and/or by carbonatation (carbonatation crimp). Displacements in the direction perpendicular to the sheet surface should in some cases be foreseen, and may be caused by minor bending of the sheet, or by displacement of the underlying support.
FIG. 1 shows a fiber cement sheet fixed to a metal frame as is known. As shown in FIG. 1, fiber cement sheets can be mechanically fixed to a metal frame by using shouldered rivets. The shoulder of the rivet, making an integral part of the metal rivet, ensures that the distance between the metal support and the outer face of the fiber cement sheet, facing away from the metal support, is kept substantially equal to the length of the shoulder. Some shoulders are wide enough to completely fill the drilling hole in the fiber cement sheet, thereby providing a so-called locked fixing. Some shoulders may have a width less then the diameter of the drilling hole, thereby allowing movement of the fiber cement sheet in the planar directions in view of the rivet. Optionally, metal sleeves are slide over rivets to cause the width of the rivet to match to the diameter of the drilling hole.
However, shouldered rivets are not only expensive to produce, but also may cause confusion for the craftsman when using two different types of shouldered rivets, one for locked fixing, the other for providing unlocked fixing points. This because these shouldered rivets may look very similar.
In case the option is taken to use rivets to provide unlocked fixing points combined with an additional metal sleeve for locked fixing points, the occasional addition of the metal sleeve may easily be forgotten during periods of repetitive action of inserting and closing rivets for providing fixing points.
When metal sleeves only are used to accommodate the width of the rivet for locked fixing points, the metal nature of the sleeve may cause damage to the drilled hole or additional stress may be enforced to the sheet at these holes, when the rivet is not perfectly perpendicularly inserted in the drilled hole. To force the optionally shouldered rivet with additional metal sleeve in the drilled hole, a significant force is needed to insert and install this rivet causing an increased risk for damaging the sheet surface.